As a wave of COVID-19 cases continues to surge across the United States, virus trackers have been eyeing another strain that may cause more infections than its predecessors. According to a leading World Health Organization official, a highly mutated variant called BA.2.86 has now been detected in Switzerland and South Africa in addition to Israel, Denmark, the U.S., and the U.K. This offshoot of the Omicron lineage carries more than 35 mutations in critical portions of the virus compared with XBB.1.5, the dominant variant through most of 2023 — about on par with the Omicron variant that caused record infections compared to its predecessor.
But because it has yet to spread widely enough to establish itself in communities, it’s too soon to know how big an impact it could have. Variants with significant changes like this one typically rattle health authorities, as they could allow the virus to evade vaccines or past infections by fooling the body’s immune system. But a risk assessment from the U.K. government says it’s tough to say what the combination of BA.2.86’s large number of mutations will mean for its ability to elude those defenses or whether it will re-energize transmission.
It’s also unclear how far the mutations extend in the virus’s genes — the underlying code determining how the virus infects and causes symptoms. And if those genes have been affected, it might change how the virus spreads and how severe the illness is, experts have said.
The US Centers for Disease Control and Prevention (CDC) and other public health officials spotted BA.2.86 last week and held meetings with scientists throughout the weekend to discuss its implications, the agency said in a statement Wednesday. The agency is monitoring cases associated with the variant and sharing sequences from it to researchers around the world so that they can track its evolution.
So far, the CDC has identified two sequences from people who have been sickened with the virus. The first, in Virginia, came from an unvaccinated older adult who had a mild virus and didn’t need to be hospitalized. The other, in Michigan, came from a person who tested positive after returning from a trip to Japan and was diagnosed through the CDC’s traveler-based genomic surveillance.
Both of the infections involving the new variant are likely linked to travel, the CDC says. According to the CDC’s risk assessment, the person in the South African case was a tourist, and the person in the U.K. traveled to Belgium before getting sick. But because those travelers don’t appear to have known each other, the risk assessment doesn’t call it an “international transmission cluster.” Read more from Scientific American here. Sara Reardon is a freelance science journalist based in Bozeman, Montana. She’s a former staff reporter for Nature and New Scientist and has worked on news and features for various national and international publications. She has a master’s degree in molecular biology.
